This disclosure relates to a continuous mining machine, and more particularly, to a continuous mining machine having a cutter drum member with extendable end portions. The present disclosure is directed to a means for extending, retracting and locking the cutter drum extensions in their extended position.
In a continuous-mining apparatus of the type employed in this invention, a cutting head mechanism is used to dislodge material from a mine vein and is operable to provide a mine passageway or room into which the apparatus advances and mining progresses. The cutting head mechanism is pivotably mounted on a mobile base to swing in a vertical plane between the mine roof and floor and includes a rotary drum cutting head assembly arranged on a horizontal transverse axis and having teeth or bits which tear away and dislodge the mineral. The apparatus also includes a conventional loading head for gathering the loose mineral on the mine floor and moving it rearwardly and inwardly towards the forward receiving portions of the conveying means of the apparatus. The rotary drum cutting assembly has end portions thereof which can be selectively extended or retracted, to respectively, dislodge mineral from the ribs and corners of the mine passageway and reduce the effective length of the cutting head assembly to provide clearance at the sides of the assembly.
As shown in FIG. 1, a continuous mining machine generally designated as 10, may assume various forms but, for illustrative purposes, herein comprises a crawler base 14 carrying a frame 16 on which a forwardly extending mining boom or support member 18 is pivotally mounted at the forward end of the frame 16 to swing up and down between a mine roof and a mine floor. An elongated mining head member 24 (also called a cutter head) extends transversely to the support member 18 and is rotatably secured thereto at the forward end thereof. The mining head member 24 is mounted for powered rotation about a longitudinal axis X-X of the head member. Pivotally mounted at the forward end of the frame 16 and extending forwardly there from beneath the support member 18 is a conventional loading head 26 having oscillatory gathering arms 28 for engaging mine mineral and moving such mineral rearwardly and inwardly towards well known conveying means 30 of the mining machine 10. Conventional hydraulic jacks (not shown) serve to swing the support member 18 in a vertical plane about the pivot axis thereof and to tilt the loading head 26 about the horizontal axis.
The elongated mining head member 24 is driven from a pair of motors 34. As shown motors 34 are in spaced axial alignment and extend generally parallel to the head member 24. A support member 18 at opposite side portions thereof suitably carries motors 34.
The drive from motors 34 rotatably drives a cutting head assembly head shaft 36. Head shaft 36 extends parallel to the longitudinal axis of the head member 24 and is captively and rotatably supported by tubular gear casing extensions 38 that also extend parallel to the longitudinal axis of the head member. The gear drive system for the mining head member may be that shown in either U.S. Pat. No. 3,617,093 or U.S. Pat. No. 3,695,725, or of other conventional construction.
As hereinafter described, head shaft 36 rotatably drives: an endless circulating belt type continuous hinge cutter chain 48, hollow cylindrical rotary drum cutting heads 50 and hollow cylindrical rotary drum cutting head extension portions 52 which include cylindrical portion 66 which are partially slideably, received within the ends of respective cutting heads 50. The portions 52 are selectively hydraulically extendable and retractable there from. An operator can selectively extend or retract the extension portions via a hydraulic control system.
Examples of conventional mining machine drum cutter extension means are shown in U.S. Pat. No. 4,489,985, and U.S. Pat. No. 3,516,712.
In U.S. Pat. No. 4,489,985, as can be seen in prior art FIGS. 2 and 3, the head shaft 36 drives the outer peripheral member 60 of the cutting head 24 via drive ring 72 which engage a plurality of circumferentially spaced keys 74. The outer peripheral member 60 is supported on casing extension 38 by bearing 76 and other internal bearings (not shown).
The hollow cylindrical rotary drum extendable end portions 52 have an inner diameter thereof larger than the outer diameter of cutting head 60 and are rotatably driven by the cutting head 60. As shown in FIGS. 2 and 3, a plurality of circumferentially spaced keys 82 has the inner ends thereof fixedly secured to the outer peripheral portion of the cutter head 60. Consequently, the head 60 drives the end portions 52 by means of keys 82 drivingly engaging respective ones of a plurality of cooperating key ways in the end portions 52. The keys 82 and the key ways 84 are circumferentially spaced about the inner periphery of the end portions 52. The above described key and key way driving arrangement additionally allows for the reciprocal axial movement of cutting head end portions 52 with respect to cutting heads 60 by the axially sliding relationship which exists between keys and key ways 82 and 84, respectively.
A hydraulic cylinder 90, in conjunction with its piston rod 92, accomplishes the extension of the end portions 52. The rod 92 is fixedly connected to plate 94 that is slidably mounted within the inner diameter of cylinder 66 of end portion 52. An annular drive ring 96 is fixedly attached to the inner diameter of cylinder 66 for movement therewith. Drive ring 96 has a plurality of holes 99 within its outer annular surface to accommodate a plurality of bolts 98 which have one end threadably engaged with the piston 94 for movement therewith and the other end fixedly attached by threads to latch release member 100. The holes 99 located on drive ring 96 have a diameter slightly larger than the diameter of bolt 98 to permit the bolts 98 to slide there through. Consequently the piston 94 and the latch release member 100 move as a unit in the direction of longitudinal axis X-X.
As can be best seen in FIG. 2, at least one latch member 102 is pivotally mounted on a mounting ring 104 that is fixedly attached to head shaft 36 for rotation therewith.
U.S. Pat. No. 3,516,712 discloses a mining machine with an extendable head having a spring return mechanism. The means for extending the extensible head is a hydraulic cylinder. More particularly, as shown in FIG. 4, there is a shaft 87 extending axially through the mining head 13. The end mining head section 70 has its telescoping cylinder part 71 slidably mounted on the shaft 87 with a key 88 in a keyway 89. A slide collar 90 is secured to the outer end of the shaft 87, and a mating inner cylinder 91 is slidably engaged with the slide collar 90 in sealed engagement. A bore 92 extends through the shaft 87 to the inner cylinder 91. Hydraulic fluid is delivered through the bore 92 into the inner cylinder 91 to move the telescoping cylinder part 71 and the end mining head section 70 outwardly relatively to the shaft 87.
A coil spring 93 is disposed between the outer mining head section 65 and the telescoping cylinder part 71. A ring 94 is secured to the outer mining head section 65 abutting one end of spring 93, and a ring 95 is secured to the inner end of the telescoping cylinder part 71 abutting the other end of spring 93. In the extended position of the end mining head section 70, as seen in FIG. 5, the spring 93 is compressed between the rings 94, 95, and the end mining head section 70 is held in its extended position by hydraulic fluid trapped within the inner cylinder 91. The end mining head section 70 is retracted by release of the hydraulic fluid from the inner cylinder 91, and the force of the spring 93 between rings 94, 95 withdraws the telescoping cylinder part along the shaft 87 and within the outer mining head section 65.